Long-distance transported Pinus pollen as a possible chronostratigraphic marker in the Scottish early postglacial

Peaks of Pinus pollen inseveraldetailed early postglacial (Flandrian) pollen diagrams from western Scotland are interpreted as the result of a change in the prevailing wind direction and intensity during climatic amelioration following the Loch Lomond Stadial (Younger Dryas). This origin implies a degree of syn-chroneity in this palynological feature, which if proven would be valuable in the poorly dated early postglacial. The absence of this palynological feature at many sites may be the result of poor sampling or stratigraphic resolution.     

Low-grade metamorphism

Diagenesis refers to those changes which take place in sediments after sedimentation but before lithification (the conversion to solid rock), while metamorphism is defined as the process whereby alterations to the composition, texture or mineralogy take place in consolidated rocks. However, the boundary between diagenesis and metamorphism is gradual/transitional and somewhat arbitrary; it cannot be sharply defined. A consequence of this is that studies of rocks affected by alteration at low temperatures and pressures have been neglected. Within the last decade, however, more attention has been focused on this type of alteration and significant advances have been made in the field of low-grade metamorphism, particularly over the last five years or so. The Caledonide rocks of Wales have been at the forefront of such investigations.     

The prospects for establishing synchroneity in the early postglacial pollen peak of Juniperus in the British Isles

Tipping, Richard M. 1987 06 01: The prospects for establishing synchroneity in the early postglacial pollen peak of Juniperus in the British Isles. Boreas , Vol. 16, pp. 155–163. Oslo. ISSN 0300–9483.
Seventy radiocarbon assays on the early postglacial Juniperus pollen peak in the British Isles are collated in order to test the hypothesis that the expansion of Juniperus was synchronous in the British Isles. The necessity of screening this data base is discussed, as are the screening procedures adopted. A number of problems concerned with screening are highlighted, which are related to the paucity of information available from which to assess the reliability of a date. The accepted radiocarbon dates are analysed by computer-generated histograms. No clear pattern of synchroneity is found. The possibility of a diachronous distribution across the British Isles is examined. The methods employed in this study illustrate the problems of using large samples of radiocarbon dates, and exemplify the stringent procedures required in handling such data.     

Origin of stratified basal ice in outlet glaciers of Vatnajökull and Öræfajökull,Iceland

Larson, G.J., Lawson, D.E., Evenson, E.B., Knudsen, Ó., Alley, R.B. & Phanikumar, M.S. 2010: Origin of stratified basal ice in outlet glaciers of Vatnajökull and Öræfajökull, Iceland. Boreas, Vol. 39, pp. 457–470. 10.1111/j.1502‐3885.2009.00134.x. ISSN 0300‐9483. During the period 2000–2005, we collected samples of englacial ice, vent water, frazil/anchor ice and stratified basal ice from warm‐based outlet glaciers of Vatnajökull and Öræfajökull, Iceland, and analysed them for ³H, ¹⁸O and D. Results of ³H analyses show that the stratified basal ice contains ³H from atmospheric thermonuclear testing and is younger than the englacial ice. Results of the ¹⁸O and D analyses show that frazil/anchor and stratified basal ice are both enriched by an average of 2.4‰ in ¹⁸O and 11‰ in D relative to vent water. These values are consistent with fractionation during partial freezing of supercooled subglacial water in an open system, one in which the remaining water is continuously removed and replenished by water of similar composition. The isotopic data and field observations do not support either a regelation or a thermal ad‐freeze‐on origin for the stratified basal ice.